Radio power supply apparatus



April 26, 1932. E. ZEPLER 1,855,375

RADIO POWER SUPPLY APPARATUS Filed Nov 14, 1929 INVENTOR 512222 ATTORN EY Patented Apr. 26, 1932 UNITED STATES PATENT OFFICE ERICH ZEPLER, OF BERLIN, GERMANY, ASSIG-NOR TO [El-IJLEFU'I ll'Kllll' GESELLSGI-IAFT FUR DRAHTLOSE TELEGRAPHIE M. B. 11., F BERLIN, GERMANY, A CORPORATION or GERMANY V RADIO POWER sUrrLY APPARATUS Application filed November 14, 1929, Serial No. 407,066, and in Germany December 19, 1928.

In receiving sets equipped with battery eliminators or power units the grid biasing potential required for the various tubes usually is produced in this manner that resistances are inserted in the plate circuit or in the filament circuit, and that the fall of potential caused across the terminals thereof is used for supplying the grid bias.

This invention pertains to means for pro ing potentials to a pair of thermionic tubes;

while Figure 2 shows an improvement in the arrangement of Figure 1.

Now, since the direct current flowing through the various resistances usually contains marked alternating current components, the wires brought to the grids 1 and 1 of tubes 2 and 2, respectively, as shown in Figure 1, must be provided with smoothing means R, C, and R, C, adapted to shut alternating current potential ofl from the grids. This method requires as many smoothing means or units R, C, and R, C", respectively, and resistances W occasioning a drop of potential as there are grid potentials to be supplied.

In the arrangement, as illustrated in Figure 2, a circuit scheme is disclosed by means of which it is feasible to provide several biasing potentials by the use of but one resistance W causing a fall of potential and of but one smoothing means B2, C2. In this scheme, inherently only one grid biasing potential 9 becomes available, namely, the highest one that is required. The other lower grid biasing potentials are imparted to the different tubes by that by the aid of another leak resistance inserted between grid and filament and being of suitable size, the desired biasing potential is provided for and supplied to the various vision.

Referring to Figure 2, suppose that the biasing potential imparted to the first tube 1. e. 2 is 6 V, and suppose that tube 2 is to be provided with a bias of 4 V, then R3 and R4 must be so chosen that R4; (R +R =2zl. Since R2 is usually low compared with R3 and R4, the condition simply becomes In like manner dififerent values of biasing potentials for additional tubes may be obtained.

It will be noted that by the use of a single current carrying resistance and one current smoothing device biasing potentials for several grids may be provided.

I claim:

1. In an energizing system for radio apparatus including a plurality of electron discharge devices some of which require biasing potentials of different values than others, ares stance common to the input-and output circuits of said devices adapted to have current flowing therethrough the drop across sa d resistance being available for supplying sald discharge devices with biasing potenltals, means for supplying one of said discharge devices with a different value of biasing potential then obtainable by the drop across said resistance comprising two resistance paths, one thereof connected between the grid of the device requiring said different value of biasing potential and one side of said first named resistance, the other connecting the other side of said first named resistance and the grid ofthe said device requiring a difierent value of biasing potential, at least one of said two last named paths being adapted to act as a grid leak resistance for the said tube requiring the different value of grid biasing potential.

2. In an energizing system for radio apparatus including a plurality of electron discharge devices some of which require grid biasing potentials, a main resistance common to'the input and output circuits of the devices requiring biasing potentials, adapted to have current flowing therethrough the drop across grids by means of potentiometer disaid resistance being available for supplying said devices with biasing potentials, means for supplying at least one of said devices with a different value of grid biasing potential then obtainable by said resistance comprising a high ohmic resistance connected between the grid of said device and one end of said main resistance and a grid leak resistance connected between the grid of said device and thetcathode thereof said last named resistance having a value which is substantially equal to the sum of the two last named resistances multiplied by the ratio of the grid biasing potential desired to be supplied to said device, to the voltage drop across said main resistance.

3. In an energizing system for radio apparatus including a plurality of electron discharge devices some of which require grid biasing potentials, means including a main resistance common to the input and output circuits of one of said devices, adapted to have current flowing therethrough whereby a biasing potential of acertain value is available for said device, means for smoothing out said biasing potential, means for supplying another of said devices with a different value of grid biasing potential smoothed out by said same smoothing means comprising a high ohmic resistance connected between the grid of said last named device and a point of said main resistance and a grid leak resistance connected between the grid of said last named tube and the cathode thereof said last named resistance having a value which is substantially the sum of the two last named resistances multiplied by the ratio of the grid biasing potential desired to be supplied to said device, to the voltage drop across the utilized portion of said main resistance.

4. In an energizing system for radio apparatus including a plurality of electron discharge devices some of which require a biasing potential of a different value than others,

" a resistance path common to the input and output circuits of said devices adapted to have current flowing therethrough whereby a biasing potential of a predetermined value is obtainable for said discharge devices, means for supplying any of said discharge devices with a different value of biasing potential than said obtainable value comprising a pair of resistance paths forming a series circuit connected across said first named resistance and having their common point connected to the grid of the tube to be furnished with a different biasing potential, said resistance paths being proportioned so that the value of grid biasing potential required bears substantially the same relation to the total potential developed across the first named resistance as the value of one of said two series resistance paths bears to the sum of the two series resistance paths and a condenser connected across said first named resistance.

5. In an energizing system for radio apparatus including a plurality of electron discharge devices some of which require biasing potentials of a different value than others, a res1stance common to the input and output circuits of said devices adapted to have current flowing therethrough whereby a predetermined value of biasing potential is available for said devices, means for supplying any of said discharge devices with a different value of biasing potential than furnished by said resistance comprising a pair of resist ance paths forming a series circuit connected across said first named resistance and having their common point connected to the grids of the tubes to be furnished with a different biasing potential, said resistance paths being proportioned so that the value of grid biasing potential required bears substantially the same relation to the total potential developed across the first-named resistance as the value of one of said two series resistance paths bears to the sum of said two series resistance paths.

ERICH ZEPLER. 

